The present disclosure relates generally to wireless sensing. More particularly, the present disclosure pertains to devices, systems, and methods for use in the passive wireless transmission of a sensed parameter (e.g., such as pH, etc.). Further, one or more exemplary devices, systems, and methods described herein include temperature compensation for the sensed parameter.
The outcome of a wide range of chemical and biological reactions are influenced by value, and thus, sensors capable of measuring pH may be desirable (see, e.g., J. B. E. Horton, S. Schweitzer, A. J. DeRouin and K. G. Ong, “A varactor-based inductively coupled wireless pH sensor,” IEEE Sensors J., vol. 11, no. 4, pp. 1061-1066, April 2011; and S. Bhadra, G. E. Bridges, D. J. Thomson and M. S. Freund, “Electrode potential based coupled coil sensor for remote pH monitoring,” IEEE Sensors J., vol. 11, no. 11, pp. 2813-2819, November 2011). It may be important to monitor and control pH in numerous fields such as structural health monitoring, environmental and food spoilage monitoring, industrial and chemical processing, and biomedical sensing (see, e.g., R.-G. Du, R.-G. Hu, R.-S. Huang and C.-J. Lin, “In situ measurement of Cl— concentrations and pH at the reinforcing steel/concrete interface by combination sensors,” Anal. Chem., vol. 78, no. 9, pp. 3179-3185. March 2006; J. M. L. Engels and M. H. Kuypers, “Medical application of silicon sensors,” J. Phys. E: Sci. Instrum., vol. 16, no. 10, pp. 987-994, 1983; J. Lin, “Recent development and applications of optical and fibre-optic pH sensors,” Trends in Analytical Chemistry, vol. 19, no. 9, pp. 541-552, September 2000; and W. D. Huang, S. Deb, Y. S. Seo, S. Rao, M. Chiao and J. C. Chiao, “A passive radio-frequency pH-sensing tag for wireless food-quality monitoring,” IEEE Sensors J., available through IEEE early access). As maintaining proper pH in blood, the digestive tract, tissues, and fluids may be essential to support optimal health, numerous efforts have been dictated to develop pH sensors for biomedical sensing (see, e.g., S. A. Grant and R. S. Glass, “A Sol-gel based fiber optic sensor for local blood pH measurements,” Sensors and Actuators B: Chemical, vol. 45, no. 1. pp. 35-42, November 1997; R. Wolthuis, D. McCrae, E. Saaski, J. Hartl and G. Mitchell, “Development of medical fiber-optic pH sensor based on optical absorption,” IEEE Trans. Biomed. Eng., vol. 39, pp. 531-537, May 1992; G. Papeschi, S. Bordi, M. Carlagrave, L. Criscione and F. Ledda, “An iridium-iridium oxide electrode for in vivo monitoring of blood pH changes,” Journal of Medical Engineering & Technology, vol. 5, no. 2, pp. 86-88, March 1981; B. R. Soller, N. Cingo and T. Khan, “Fiber optic sensing of tissue pH to assess low blood flow states,” in Proc. IEEE Sensors, 2002, pp. 266-269; T. Ativanichayaphong, J. Wang, W.-D. Huang, S. Rao, H. F. Tibbals, S.-J. Tang, S. J. Spechler, H. Stephanou and J.-C. Chiao, “Development of an implanted RFID impedance sensor for detecting Gastroesophageal reflux,” in Proc. IEEE International Conference on RFID, 2007, pp. 127-133; T. Ativanichayaphong, S.-J. Tang, L.-C. Hsu, W.-D. Huang, Y.-S. Seo, H. F. Tibbals, S. Spechler and J.-C. Chiao, “An implantable batteryless wireless impedance sensor for Gastroesophageal reflux diagnosis,” in Proc. IEEE MIT-S International Microwave Symposium Digest, 2010, pp. 608-611; E. I. Gill, A. Arshak, K. Arshak and O. Korostynska, “Investigation of thick-film polyaniline-based conductimetric pH sensors for medical applications,” IEEE Sensors J, vol. 9, no. 5, pp. 555-562, May 2009). In environmental monitoring applications, pH sensors have been found useful for monitoring pH of the soil (e.g., pH of a soil solution) and drinking water (see, e.g., S. G. Lemos, A. R. Nogueira, A. Torre-Neto, A. Parra and J. Alonso, “Soil calcium and pH monitoring sensor system,” J. Agric. Food Chem., vol. 55, no. 12, pp. 4658-4663. June 2007; and A. Dybko, W. Wróblewski, E. Roźniecka, K. Poźniakb, J. Maciejewski, R. Romaniuk and Z. Brźozka, “Assessment of water quality based on multiparameter fiber optic probe,” Sensors and Actuators B: Chemical, vol. 51 no. 1-3, pp. 208-213, August 1998). Further, pH sensors may be useful in many industrial manufacturing processes (see, e.g., J. Lin, “Recent development and applications of optical and fibre-optic pH sensors,” Trends in Analytical Chemistry, vol. 19, no. 9, pp. 541-552, September 2000). pH sensors have further been applied to monitor pH change during food production (see, e.g., J. B. E. Horton, S. Schweitzer, A. J. DeRouin and K. G. Ong, “A varactor-based inductively coupled wireless pH sensor,” IEEE Sensors J., vol. 11, no. 4, pp. 1061-1066, April 2011), for food spoilage monitoring (see, e.g., W. D. Huang, S. Deb, Y. S. Seo, S. Rao, M. Chiao and J. C. Chiao, “A passive radio-frequency pH-sensing tag for wireless food-quality monitoring,” IEEE Sensors J., available through IEEE early access), and for localized corrosion (see, e.g., A. A. Panova, P. Pantano, D. R. Walt, “In situ fluorescence imaging of localized corrosion with a pH sensitive imaging fiber,” Anal. Chem., vol. 69, no. 8, pp. 1635-1641, April 1997). In structural health monitoring, the value of pH may be a crucial factor for assessing the deterioration of reinforced concrete structures. Further, in situ measurement of pH at the reinforcing steel/concrete interface has been used for monitoring the corrosion process (see, e.g., R.-G. Du, R.-G. Hu, R.-S. Huang and C.-J. Lin, “In situ measurement of Cl— concentrations and pH at the reinforcing steel/concrete interface by combination sensors,” Anal. Chem., vol. 78, no. 9, pp. 3179-3185. March 2006).
The sensors described herein may be used to measure parameters of a wide variety of materials such as milk or biomaterials. Milk is widely consumed across the world and its freshness is an important factor for public health. Milk spoilage may result in food poisoning and disease outbreaks, and as such, monitoring the quality of milk during transportation and storage may be beneficial (see, e.g., W. D. Huang, S. Deb, Y. S. Seo, S. Rao, M. Chiao and J. C. Chiao, “A passive radio-frequency pH-sensing tag for wireless food-quality monitoring,” IEEE Sensors J, vol. 12, no. 3, pp. 487-495, March 2012).
Bacteria growth is a source of milk spoilage (see, e.g., W. D. Huang, S. Deb, Y. S. Seo, S. Rao, M. Chiao and J. C. Chiao, “A passive radio-frequency pH-sensing tag for wireless food-quality monitoring,” IEEE Sensors J., vol. 12, no. 3, pp. 487-495, March 2012; K. G. Ong, J. S. Bitler, C. A. Grimes, L. G. Puckett and L. G. Bachas, “Remote query resonant-circuit sensors for monitoring of bacteria growth: application to food quality control,” Sensors, vol. 2, pp. 219-232, 2002; and N. Nicolaou and R. Goodacre, “Rapid and quantitative detection of the microbial spoilage in milk using Fourier transforminfrared spectroscopy and chemometrics,” The Analyst, vol. 133, no. 10, pp. 1424-1431, July 2008). Standard plate count or psychrotrophic bacteria count may be used to monitor bacteria concentration in milk. However, standard plate count or psychrotrophic bacteria count methods may be time consuming and labor intensive. Further, although microbiological impedance devices may provide a less labor intensive way to estimate bacteria count, such microbiological impedance devices can also introduce contamination (see, K. G. Ong, J. S. Bitler, C. A. Grimes, L. G. Puckett and L. G. Bachas, “Remote query resonant-circuit sensors for monitoring of bacteria growth: application to food quality control,” Sensors, vol. 2, pp. 219-232, 2002).
Another common milk freshness monitoring method may utilize a gas sensor. Gas sensors may be made of metal oxide semiconductors, conducting organic polymers or piezoelectric crystals, and may rely on changes of conductivity of sensing films induced by the adsorption of gases and subsequent surface reactions that are produced by milk during spoilage processes. Gas sensors may be easily affected by environmental conditions such as moisture and temperature (see, e.g., W. D. Huang, S. Deb, Y. S. Seo, S. Rao, M. Chiao and J. C. Chiao, “A passive radio-frequency pH-sensing tag for wireless food-quality monitoring,” IEEE Sensors J., vol. 12, no. 3, pp. 487-495, March 2012). As such, a simple, cost effective and remote milk quality monitoring sensor that can be embedded in the milk container as milk freshness indicator may be desired.
Bioreactors are most commonly used for carrying out bioprocesses to produce many commodities and chemicals. During bioprocesses, optimal cell growth may depend on pH control and many cells produce acids as a metabolic by-product. Therefore, monitoring and regulating the pH of the biological medium may be important for successful bioreactor operation (see, e.g., P. Harms, Y. Kostov and G. Rao, “Bioprocess monitoring,” Current Opinion in Biotechnology, vol. 13, no. 2, pp. 124-127, April 2002; and A. S. Jeevarajan, S. Vani, T. D. Taylor and M. M. Anderson, “Continuous pH monitoring in a perfused bioreactor system using an optical pH sensor,” Biotechnology and Bioengineering, vol. 78, no. 4, pp. 467-472, May 2002).
Sterilizable electrochemical pH probes may be used for bioprocess monitoring. Such electrochemical pH probes, however, may require a wired connection for data exchange, and, as such, are inherently invasive. Shake flasks and test tubes are regularly used in academia as well as in industry for selection and bioprocess development. The use of wired pH probes for multiple reactors (e.g., to simultaneously monitor several shake flasks) may require a proportional increase of wiring, cost and complexity, and as such, non-invasive sensors may be an attractive alternative (see, e.g., S. Vuppu, Y. Kostov and O. Rao, “Economical wireless optical ratiometric pH sensor,” Meas. Sci. Technol., vol. 20, pp. 045202(7pp), February 2009; C. Komives and R. S. Parker, “Bioreactor state estimation and control,” Current Opinion in Biotechnology, vol. 14, no. 5, pp. 468-474, October 2003; A. Vasala, J. Panula, M. Bollóa, L. Illmann, C. Hálsig and P. Neubauer, “A new wireless system for decentralized measurement of physiological parameters from shake flask,” Microbial Cell Factories, vol. 5, no. 8, pp. 1-6, February 2006; and S. Kumar, C. Wittniann and E. Heinzle, “Minibioreactors,” Biotechnology Letters, vol. 26, no. 1, pp. 1-10, January 2004).
Very few non-invasive pH sensors may be used inside bioreactors because most pH sensors cannot endure the harsh bioprocess environment inside a bioreactor, e.g., because the medium may permeate through and damage the sensor. Further, the fluid medium culture may not be well defined, which may interfere with the sensor readings. Moreover, sterilization of the sensors used in bioprocesses may be required to avoid medium contamination so as to not interfere with metabolism (see, e.g., P. Harms, Y. Kostov and G. Rao, “Bioprocess monitoring,” Current opinion in Biotechnology, vol. 13, no. 2, pp. 124-127, April 2002). Non-invasive optical sensors based on absorbance or fluorescence from pH-sensitive dyes have been used inside bioreactors. Optical sensors, however, may suffer from a narrow operating range and drifting over time (see, e.g., W.-L Tsai, S. L. Autsen, J. Ma, T. Hudson and J. Luo, “Noninvasive optical sensor technology in shake flasks for mammalian cell cultures,” BioProcess International, vol. 10, no. 1, pp. 50-56, January 2012; and H. R. Kermis, Y. Kostov, P. Harms and G. Rao, “Dual excitation ratiometric fluorescent pH sensor for noninvasive bioprocess monitoring: development and application,” Biotechnology Progress, vol. 18, no. 5, pp. 1047-1053, September 2002).